We aim to understand the relationship between material structure and its dynamics (i.e. relaxation) in a sheared 2D colloidal sample (a,b) . A custom-made interfacial stress rheometer is used to measure the bulk flow rheology while simultaneously characterizing the fluid microstructure (i.e. particle rearrangements). We use the concept of excess entropy, a structural order parameter, to characterize the microstructure since it can be computed from the sample’s pair correlation function g(r) (c). Our results sow that the strain rate in the sample, the relaxation rate induced by plastic flow, and the sample micro-structure are measured to oscillate together but with different phases (d). Above the yielding transition, during plastic flow, we find that excess entropy scales with relaxation time (e). These results imply that bulk strain proceeds particle dynamics, which in turn proceeds evolution of structure.
 Galloway, K. L. et. Al., Proceedings of the National Academy of Sciences 117, 11887-11893 (2020).